Molecular data and morphological, ecological, and demographic analyses suggest that the Panamanian golden frogs and their kin (the Atelopus varius-zeteki clade) are comprised of five distinct forms (Zippel et al., 2006). Additional analyses identify phenotypic and genetic differentiation consistent with proposed Evolutionarily Significant Units (ESUs), and support the status of Atelopus varius and Atelopus zeteki as separate species (Richards and Knowles, 2007).

Justification:
Listed as Critically Endangered because of a drastic population decline, estimated to be more than 80% over the last three generations, inferred from the apparent disappearance of most of the population, probably due to chytridiomycosis.

This species is known from both Atlantic and Pacific versants of the cordilleras of Costa Rica and western Panama, up to 2,000m asl. It is also present on outlying ridges and hills down to 16m asl at a few lowland sites. The species is absent from the lowlands of the Pacific north-west (Savage 2002). Records from Colombia are in error. Recent declines have reduced the Costa Rican range to only one known locality, Fila Chonta, 10km north-west of the city of Quepos.

Over 100 populations of this species were known from Costa Rica where it was often quite common. Drastic declines began in Monteverde in 1988 and the species was thought to have been extirpated in Costa Rica by 1996. However, after nearly eight years during which the species was thought to be extinct, a remnant population was discovered near Quepos, on the Pacific coastal range, in 2003, and was surveyed again in 2005 when more individuals were found. In Panama, some populations have declined, but others persist. For example, Lips (1999) reported a mass mortality in Fortuna, Provincia de Chiriquí, which affected this species in December 1996-January 1997. This site was visited again in February 1998, but the species was not found (Ibáñez 1999). It has been recorded in Panama as recently as November 2002, but it is believed to still be in serious decline.

It is a terrestrial species of humid lowland and montane forest; specimens recorded at lowland rainforest localities were all found along high-gradient, rocky streams, in hilly areas (Savage 2002). It is associated with small fast-flowing streams and is often found along the banks and sitting out on rocks in streams; at night they sleep in crevices or low vegetation. They forrmely occurred in large concentrations during the dry season, from December to May (Savage 2002). Eggs are laid in water and are probably attached to rocks.

The major threat is likely to be chytridiomycosis, which has led to catastrophic population declines in many other montane species of Atelopus. Museum specimens of this species have been found to have chytrid fungi. One specimen collected in 2003 from the only known site at which the species survives in Costa Rica tested positive for chytrid infection, and the disease was also confirmed in individuals in 1986, 1990, 1992 and 1997. Other threats to the species include habitat loss due to the destruction of natural forests, and predation by introduced trout. The only known site in Costa Rica is under serious threat of a landslide that could potentially destroy the entire stream section where they are presently found. It was collected by the thousands in the 1970s and shipped to Germany as part of the international pet trade.

The species is present in three protected areas in Panama, and was previously found in a number of Costa Rican protected areas. Ex-situ conservation measures are now needed to ensure the future survival of this species, and a captive-breeding program has been initiated.